Thursday, December 8, 2011

Wednesday Wizardry

No, this is not the title of a new Harry Potter novel. If it were, there would be lines of people in front of the ICC Birmingham days ago where the UKOUG conference took place. Instead there was a modest but very interested group of spectators assembled who were interested in how to rapidly build an enterprise application based on SOA and BPM principles using Oracle Fusion Middleware in only a couple of hours.

Let's step back a little bit. This year at the ODTUG Kaleidoscope conference in Long Beach a team of Dutch ACEs and ACE Directors took part in a rapid software development session called Thursday Thunder. The format is to have a small team of experienced developers that each build components of an enterprise application in parallel. The application consists of a business process, services, and a frontend. Such an approach is possible since the application is developed in a SOA-fashion: based on loosely-coupled components with well-defined interfaces that can be easily integrated. The developers' laptops are hooked up to projectors so the crowd can watch whatever developer, programming, and tools they are interested in. You'll also experience the interactions between developers and the pros and cons of the decisions they make. Moderators will question these choices, take questions from the audience, explain the design choices, interview the developers, and act as (annoying) stakeholder to the developers to spice things up a little bit. After a conference filled with theory and small demos, a final live development session showing all these concepts and resulting in a concrete result (a working application) in real-life is fun to watch!

Due to the success of the session at Kaleidoscope the format was copied at DOAG by our German and Swiss fellow ACEs and ACE Directors and repeated for this years UKOUG conference in Birmingham: Wednesday Wizardry! Goal was to develop an application supporting a conference and its speakers by implementing a speakers business process (submit an abstract, review and accept or reject it, invite a speaker, upload the presentation, collect evaluations, and so on).

Now we had a small setback with the original team. We lost some developers and moderators due to an ice hockey accident and last minute meetings. Of the original team only Lonneke Dikmans (Vennster), Lucas Jellema (Amis), and Ronald van Luttikhuizen (Vennster) remained. Luckily, Simon Haslam and John King were willing to step up as moderators!

So what were the three of us supposed to build in a three hour window? The figure below shows an overview of the various components involved. Lonneke would implement the speakers business process (blue) using Oracle SOA Suite 11g, Lucas would realize the user interface (yellow) using ADF 11g, and Ronald would develop the services (red) using Oracle SOA Suite 11g as well.

Overview of Wednesday Wizardry case

The team prepared only the database (green) and the interface of the services (so its WSDLs and XSDs) in advance. The rest was build from scratch.

In the beginning we had Murphy pay us a visit: There were some network problems and the VM on which the server was running was not reachable. Thanks to Alex Gorbachev, tips & tricks from the audience, and help from the tech guys we managed to solve the connectivity issues. In somewhat more than the two hours that were left the team was able to develop almost all of the functionality shown in the image and do a live demo for the "manager" (Simon was kind enough to play for manager, it was scary how well he did that...) at the end of the session. All steps from submitting an abstract to the acceptance and indicating the session was done were successfully executed!

Wednesday Wizardry Team in action; from left to right: Lonneke, Ronald and Lucas

Some general key take-aways:

SOA helps in breaking up systems into well-defined services that can be easily integrated. Thereby reducing complexity of components, speeding up development, and enabling parallel implementation.

A bigger development team is not always the best choice. A small experienced team can realize software fast(er) with less communication overhead.

Live enterprise application development in a few hours is doable and fun for both audience as well as developers. Things can go wrong and will go wrong, but these are the same issues real software development teams run into.

Some specific and technical take-aways:

Use MDS to store your service interfaces (WSDLs and XSDs); even for small projects! We didn't use MDS as team (too little preparation time) and as a side-effect had some troubles with defining service references for Web Services that pointed to local artefacts that were unreachable from the developers' machine.

Use scripting for deployment for predictable and less error-prone deployment of software components.

The out-of-the-box worklist application is an excellent tool in testing a busines sprocess. You don't need a working user interface that interacts with the Human Workflow components to test the business process.

Never overwrite a database trigger that enqueues an event on AQ with a trigger that selects sysdate from dual 5 minutes before the final demo :-)

So, what will be the next live application development session after Thursday Thunder and Wednesday Wizardry? Friday Fantasy, Monday Maniac, Tropic Tuesday? Our team is ready for it :-)